Aha, right you are!
Font settings have always been saved when switching memes, but now that we added custom default font settings, this had the unintended side effect of not switching back to white/black/impact when selecting a non-customized meme. This part should be fixed now.
Default fonts have been a missing feature for a long time, and sadly/hilariously I think Imgflip is somewhat responsible worldwide for killing some of the original nature of some memes because we lacked some customization ability (and Imgflip might be worldwide #1 meme generator at this point..). For example, Doge originally uses comic sans and multiple colors (
imgflip.com/memegenerator/Doge). Comics do better with Arial and no text shadow, because it is MUCH more readable when the font gets small in those tiny chat bubbles. The reason all-caps/impact/black/white is the default is due to the original Advice Animal style which only uses a top and bottom caption on a simple character, and using extreme contrast (white on black) ensures the font is readable on any possible image background. Many memes have evolved far beyond that style now and so people are starting to use a wider variety of font settings.